..In addition, the East African Hadza and Sandawe derive a fraction of their ancestry from admixture with a population related to the Khoisan, supporting the hypothesis of an ancient link between southern and eastern Africa...

..However, thousands of samples have been previously collected from these cell types, and saliva collection has the advantage that it is a non-invasive and appropriate for a wide variety of research...

..Our results emphasize that replication of disease association for specific rare genetic variants across diverged populations must overcome both reduced statistical power because of rarity and higher population divergence...

History of click-speaking populations of Africa inferred from mtDNA and Y chromosome genetic variation

Sarah A TishkoffDepartment of Biology, University of Maryland, USAMol Biol Evol 24:2180-95. 2007